||These files were generated following the ACS WFC anneal on November 14, 2019, and should be used to calibrate ACS WFC observations taken between October 17, 2019 and November 14, 2019.
||These WFC3 UVIS superdarks, drk, and CTE corrected superdarks, dkc, will affect all UVIS data taken from October 4th through October 26th 2019. Currently, the automated calibration pipeline and Calibration Reference Data System only have WFC3 UVIS drk and dkc reference files up to a USEAFTER date of September 30th 2019. The automated pipeline should now use these reference files to perform dark subtraction on any UVIS datasets obtained between the dates above because they represent the most accurate estimate of the dark current and hot pixels at the time of the science observation. These WFC3 UVIS drk and dkc files were generated using dark exposures from the HST Cycle 26 daily monitoring program 15571 and 15567. More information regarding the method used to create UVIS dark calibration reference files can be found in WFC3 ISR 2016 08. Additionally, the header of each reference file has a detailed history section outlining the process and provides a list of datasets used to create each file.
||This ACS SBC IMPHTTAB delivery corrects a 15 to 30 percent error in the SBC absolute photometric calibration, and also introduces corrections for the time-dependent sensitivity for the SBC. Use of this file necessitates the use of CALACS versions greater than or equal to 10.2.1. For more information about the correction to the SBC photometry and the time-dependent sensitivity, see ACS ISRs 2019-04 and 2019-05.
||These files were generated following the ACS WFC anneal on October 17, 2019, and should be used to calibrate ACS WFC observations taken between September 21, 2019 and October 17, 2019.